package org.apache.lucene.store;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

/**
 * Use this {@link LockFactory} to disable locking entirely. This LockFactory is
 * used when you call {@link FSDirectory#setDisableLocks}. Only one instance of
 * this lock is created. You should call {@link #getNoLockFactory()} to get the
 * instance.
 * 
 * @see LockFactory
 */

public class NoLockFactory extends LockFactory {

	// Single instance returned whenever makeLock is called.
	private static NoLock singletonLock = new NoLock();
	private static NoLockFactory singleton = new NoLockFactory();

	public static NoLockFactory getNoLockFactory() {
		return singleton;
	}

	public Lock makeLock(String lockName) {
		return singletonLock;
	}

	public void clearLock(String lockName) {
	};
};

class NoLock extends Lock {
	public boolean obtain() throws IOException {
		return true;
	}

	public void release() {
	}

	public boolean isLocked() {
		return false;
	}

	public String toString() {
		return "NoLock";
	}
}
